For many years, the eyes of an individual have been tested to discover visual deficiencies. However, no accurate repeatable tests have been suggested for determining the visual integrity of the individual's eyes. That is, no accurate repeatable tests have been suggested to measure the functioning of the retina, the optic nerves, optic radiations and the occiptial lobes. The necessity of such a test is important in several areas. For instance, such testing is necessary to determine whether the individual has an optic nerve dysfunction. Also, such testing is necessary to make a diagnosis or determination of a disease where temporal variations in the course of the disease is an important factor, such as in the determining whether the individual is sufffering from ischemic optic neuropathy or from multiple schlerosis. Moreover, such testing is necessary as an aid in determining the effectiveness of the therapy once the disease is diagnosed.
It has been suggested that amblyopia in certain individuals could be a measurement of visual integrity. This utilizes a device for providing a single light base level to one eye. A neutral density optical wedge was positioned in front of the opposite eye to vary the light intensity in that eye. The individual then moved the neutral density optical wedge to a position where the perceived light was of equal intensity. The results obtained, however, were confusing. It is believed these confusing results were caused because the eyes of the individual were not permitted to adjust to an equal amount of light intensity prior to the adjustment made with the wedge. Further, this apparatus was quite expensive and difficult to use.
Accordingly, it is an object of this invention to provide a method of and apparatus for testing the visual integrity of an individual in an accurate, effective and repeatable manner.
Further, it is an object of the present invention to provide a method of an apparatus for testing the visual integrity of an individual to determine optic nerve dysfunction by providing light to the eyes in wavelengths of blue, red, yellow and green.
Further, it is an object of the invention to provide a method of and apparatus for testing the visual integrity of an individual at three intensity levels in order to place the eyes in scotopic, mesopic and photopic conditions.
In accordance with the invention, a method of and apparatus for testing the visual integrity of an individual is provided. Initially an equal amount of visible light intensity is provided to the right and left eye of the individual by illuminating a target with equal light intensity and having the individual view the target through a binocular viewing mechanism to provide orthophoric viewing. The eyes of the individual are adapted to the equal intensities for an adaptation period. The individual then adjusts the light intensity in both eyes until the perceived light is equal. A measurement is then made of the difference between the light intensity provided at the right eye and the light intensity provided at the left eye as an indication of the visual integrity of the individual's right eye compared to the left eye.